U.S. patent number 8,147,766 [Application Number 13/098,968] was granted by the patent office on 2012-04-03 for selective, integrated processing of bio-derived ester species to yield low molecular weight hydrocarbons and hydrogen for the production of biofuels.
This patent grant is currently assigned to Chevron U.S.A. Inc.. Invention is credited to Peter C. Ricci, Kerry K. Spilker, James F. Stevens, Roger Vogel.
United States Patent |
8,147,766 |
Spilker , et al. |
April 3, 2012 |
Selective, integrated processing of bio-derived ester species to
yield low molecular weight hydrocarbons and hydrogen for the
production of biofuels
Abstract
The present invention relates to methods and systems for
processing biomass to selectively yield a variety of hydrocarbon
molecules and hydrogen as products, wherein some or all of these
products can be further utilized for other biomass processing
sub-processes, particularly wherein they lead to the generation of
biofuels and/or other high-value products.
Inventors: |
Spilker; Kerry K. (Houston,
TX), Vogel; Roger (Fairfield, CA), Stevens; James F.
(Katy, TX), Ricci; Peter C. (Spring, TX) |
Assignee: |
Chevron U.S.A. Inc. (San Ramon,
CA)
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Family
ID: |
42229885 |
Appl.
No.: |
13/098,968 |
Filed: |
May 2, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110211998 A1 |
Sep 1, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12330306 |
Dec 8, 2008 |
7960598 |
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Current U.S.
Class: |
422/187; 585/733;
585/240; 44/386; 44/605; 585/304; 585/242; 585/310; 560/1; 44/385;
585/302; 44/606; 585/303; 585/241; 560/129 |
Current CPC
Class: |
C01B
3/32 (20130101); C10G 3/52 (20130101); C10B
53/02 (20130101); C11C 3/12 (20130101); C10L
1/026 (20130101); C11C 3/123 (20130101); C11C
3/10 (20130101); C07C 67/03 (20130101); C10G
3/50 (20130101); C10L 1/08 (20130101); C10G
3/46 (20130101); C07C 67/03 (20130101); C07C
69/52 (20130101); Y02E 50/32 (20130101); C01B
2203/0205 (20130101); C10L 2290/544 (20130101); C10L
2200/0469 (20130101); C10G 2300/1011 (20130101); C10L
2290/02 (20130101); C01B 2203/065 (20130101); Y02E
50/14 (20130101); C10L 2200/0492 (20130101); Y02E
50/30 (20130101); Y02P 30/20 (20151101); Y02E
50/10 (20130101); C10L 2200/0446 (20130101); C10L
2290/04 (20130101); Y02E 50/13 (20130101); C10G
2300/1014 (20130101); C10G 2300/42 (20130101); C01B
2203/1217 (20130101) |
Current International
Class: |
B01J
8/00 (20060101) |
Field of
Search: |
;585/240-242,302-304,310,733 ;44/385-386,605-606 ;560/1,129 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Chen et al., "Catalytic pyrolysis of biomass for hydrogen rich fuel
gas production," Energy Conversion & Management, vol. 44, pp.
2289-2296, 2003. cited by other .
Dry, "The Fischer-Tropsch process: 1950-2000," Catalysis Today,
vol. 71, pp. 227-241, 2002. cited by other .
Huber et al., "Synthesis of Transportation Fuels from Biomass:
Chemistry, Catalysts, and Engineering," Chem. Rev., vol. 106, pp.
4044-4098 (2006). cited by other .
Lappas et al., "Biomass pyrolysis in a circulating fluid bed
reactor for the production of fuels and chemicals," Fuel, vol. 81,
pp. 2087-2095, 2002. cited by other .
Marquevich et al., "Steam Reforming of Sunflower Oil for Hydrogen
Production," Ind. Eng. Chem. Res., vol. 39, pp. 2140-2147, 2000.
cited by other .
Rana et al., "A Review of Recent Advances on Process Technologies
for Upgrading of Heavy Oils and Residua," Fuel, vol. 86, pp.
1216-1231 (2007). cited by other .
Wang et al., "Biomass to Hydrogen via Fast Pyrolysis and Catalytic
Steam Reforming of the Pyrolysis Oil or Its Fractions," Ind. Eng.
Chem. Res., vol. 36, pp. 1507-1518, 1997. cited by other.
|
Primary Examiner: Griffin; Walter D
Assistant Examiner: McCaig; Brian
Attorney, Agent or Firm: Mickelson; Edward T.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application for patent is a Divisional of U.S. patent
application Ser. No. 12/330,306, now U.S. Pat. No. 7,960,598, filed
Dec. 8, 2008.
Claims
What is claimed:
1. A system for generating a hybrid diesel fuel product, said
system comprising: a) an extraction unit for treating a
triglyceride-containing biomass so as to yield a triglyceride
fraction comprising triglycerides and a non-triglyceride fraction;
b) a transesterification unit for transesterifying a first portion
of the triglycerides in the triglyceride fraction to yield
monoesters; c) a steam-reforming unit for converting a second
portion of the triglycerides in the triglyceride fraction into
bio-derived H.sub.2; d) a hydroprocessing reactor for
hydroprocessing at least a portion of the monoesters with H.sub.2
to yield one or more hydrocarbon products of a first type, wherein
a portion of the H.sub.2 so utilized is provided by the bio-derived
H.sub.2; and e) a pyrolysis unit operable for pyrolyzing at least a
portion of the non-triglyceride fraction to pyrolysis oil, at least
a portion of which is hydroprocessed in the hydroprocessing reactor
to yield one or more hydrocarbon products of a second type.
2. The system of claim 1, wherein the pyrolysis unit is further
operable for co-pyrolyzing the non-triglyceride fraction with a
secondary biomass, wherein the secondary biomass is selected from
the group consisting of triglyceride-containing biomass,
lignocellulosic biomass, cellulosic biomass, and combinations
thereof.
3. The system of claim 1, wherein the steam-reforming unit is
operable for co-reforming a portion of the monoesters with the
triglycerides to yield bio-derived H.sub.2, and wherein said
co-reforming is done either sequentially or in parallel.
4. The system of claim 1, wherein said system is configured such
that intermediate divergent pathways afford dynamic process
adaptability.
5. The system of claim 1, further comprising a stripping unit for
stripping CO from the bio-derived H.sub.2.
6. The system of claim 1, wherein the hydroprocessing unit utilizes
a catalyst selected from the group consisting of Co--Mo, Ni--Mo,
noble metals, and combinations thereof.
7. The system of claim 1, further comprising a Fischer-Tropsch unit
that utilizes at least some of the bio-derived H.sub.2.
8. The system of claim 1, wherein the one or more hydrocarbon
products of the first and second type generated by said system are
independently selected from the group consisting of Generation 1
biofuels, Generation 2 biofuels, biolubricants,
biologically-derived petrochemicals, and combinations thereof.
9. The system of claim 1, wherein the one or more hydrocarbon
products of the first and second type generated by said system are
provided via multiple product streams.
10. The system of claim 9, configured such that product output from
the multiple product streams is amenable to dynamic variation.
Description
FIELD OF THE INVENTION
The present invention relates to methods and systems for processing
biomass to selectively yield a variety of hydrocarbon molecules and
hydrogen as products, wherein some or all of these products can be
further utilized for other biomass processing sub-processes,
particularly wherein they lead to the generation of biofuels and/or
other high-value products.
BACKGROUND
Many methods have been suggested for utilizing biofuel for energy
production in order to compensate for at least a portion of the
fossil fuel currently used in such energy production, and thereby
also decrease net CO.sub.2 emissions in the overall energy
production cycle. See, e.g., Huber et al., "Synthesis of
Transportation Fuels from Biomass: Chemistry, Catalysts, and
Engineering," Chem. Rev., vol. 106, pp. 4044-4098, 2006.
Unfortunately, biofeedstocks are generally considered to be low
energy fuels, and not easily utilized for energy production. The
low energy content of biomass renders it generally inadequate for
high-efficiency production of energy, such as high-temperature,
high-pressure steam or electricity. Additionally, non-uniformity in
the raw material (i.e., biomass), differences in its quality, and
other similar hard-to-control variations, may cause problems in an
energy production cycle that relies heavily on such fuel.
In view of the foregoing, methods and/or systems for enhancing
and/or integrating a variety of biofuel synthesis routes with each
other, and/or with traditional refinery processes, would be
extremely useful--particularly wherein they can provide dynamic
adaptability in terms of their ability to accommodate change in
either or both of their feedstock material and their product
stream(s).
BRIEF DESCRIPTION OF THE INVENTION
So as to address at least some of the above-described limitations
and/or recognized needs of biofuels and/or their processing, in
some embodiments the present invention is directed to methods
(i.e., processes) and systems by which various biomass feedstock
processing routes can be integrated with each other and/or with
other conventional refinery processes. Advantages of such
integration include, but are not limited to, dynamic adaptability.
Dynamic adaptability affords the ability to rapidly react to
changes/variability in the feedstocks and/or product streams,
whether such change/variation is desired or not.
In some embodiments, the present invention is directed to one or
more methods comprising the steps of: (a) treating a
triglyceride-containing biomass so as to yield a triglyceride
fraction comprising triglycerides and a non-triglyceride fraction;
(b) transesterifying a first portion of the triglycerides in the
triglyceride fraction to yield monoesters; (c) steam-reforming a
second portion of the triglycerides in the triglyceride fraction to
yield bio-derived H.sub.2; (d) hydroprocessing at least a portion
of the monoesters with H.sub.2 in a hydroprocessing reactor to
yield one or more hydrocarbon products of a first type, wherein a
portion of the H.sub.2 so utilized is provided by at least a
portion of the bio-derived H.sub.2; and (e) pyrolyzing at least a
portion of the non-triglyceride fraction to yield a pyrolysis oil,
at least a portion of which is hydroprocessed in the
hydroprocessing reactor to yield one or more hydrocarbon products
of a second type.
In some or other embodiments, the present invention is directed to
one or more systems for implementing the above-mentioned methods,
said systems comprising: (a) an extraction unit for treating a
triglyceride-containing biomass so as to yield a triglyceride
fraction comprising triglycerides and a non-triglyceride fraction;
(b) a transesterification unit for transesterifying a first portion
of the triglycerides in the triglyceride fraction to yield
monoesters; (c) a steam-reforming unit for converting a second
portion of the triglycerides in the triglyceride fraction into
bio-derived H.sub.2; (d) a hydroprocessing reactor for
hydroprocessing at least a portion of the monoesters with H.sub.2
to yield one or more hydrocarbon products of a first type, wherein
a portion of the H.sub.2 so utilized is provided by the bio-derived
H.sub.2; and (e) a pyrolysis unit operable for pyrolyzing at least
a portion of the non-triglyceride fraction to pyrolysis oil, at
least a portion of which is hydroprocessed in the hydroprocessing
reactor to yield one or more hydrocarbon products of a second
type.
The foregoing has outlined rather broadly the features of the
present invention in order that the detailed description of the
invention that follows may be better understood. Additional
features and advantages of the invention will be described
hereinafter which form the subject of the claims of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, and the
advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
FIG. 1 illustrates, in flow diagram form, methods for integrating
biomass processing routes, in accordance with some embodiments of
the present invention; and
FIG. 2 depicts, schematically, systems for implementing methods
such as illustrated in FIG. 1, in accordance with some embodiments
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
1. Introduction
Embodiments of the present invention are directed, at least in
part, to methods (processes) and systems for processing biomass to
selectively yield a variety of hydrocarbon molecules and hydrogen
as products, wherein some or all of these products can be further
utilized for other biomass processing sub-processes via process
integration, so as to yield biofuels and/or other high-value
products.
A unique aspect of at least some such above-described embodiments
of the present invention is the dynamic adaptability such methods
and systems derive from various levels of process integration.
Because biomass composition is rarely seen as constant, economic
large-scale processing of such material for the production of
biofuels must be tolerant of variability inherent to biomass
feedstocks. Such adaptability and variation tolerance also lends
itself to increased flexibility in modulating the output of product
and/or intermediate streams, as the need arises.
2. Definitions
Certain terms and phrases are defined throughout this description
as they are first used, while certain other terms used in this
description are defined below:
The prefix "bio," as used herein, refers to an association with a
renewable resource of biological origin, such resources generally
being exclusive of fossil fuels.
A "biologically-derived oil," as defined herein, refers to any
triglyceride-containing oil that is at least partially derived from
a biological source such as, but not limited to, crops, vegetables,
microalgae, and the like. Such oils may further comprise free fatty
acids. The biological source is henceforth referred to as
"biomass." For more on the advantages of using microalgae as a
source of triglycerides, see R. Baum, "Microalgae are Possible
Source of Biodiesel Fuel," Chem. & Eng. News, vol. 72(14), pp.
28-29, 1994. Herein, the terms "vegetable oil," "crop oil," and
"biologically-derived oil" will generally be used
interchangeably.
"Triglyceride," as defined herein, refers to the class of molecules
having the following molecular structure:
##STR00001## where x, y, and z can be the same or different, and
wherein one or more of the branches defined by x, y, and z can have
unsaturated regions.
A "triglyceride-containing biomass," as described herein, is any
biomass material from which triglyceride species can be
extracted.
A "carboxylic acid" or "fatty acid," as defined herein, is a class
of organic acids having the general formula:
##STR00002## where "R" is generally a saturated (alkyl)hydrocarbon
chain or a mono- or polyunsaturated (alkenyl)hydrocarbon chain.
"Lipids," as defined herein, broadly refers to the class of
molecules comprising fatty acids, and tri-, di-, and
monoglycerides.
"Hydrolysis" of triglycerides yields free fatty acids and glycerol,
such fatty acid species also commonly referred to as carboxylic
acids (see above).
"Transesterification," or simply "esterification," refers to the
reaction between a fatty acid and an alcohol to yield an ester
species.
"Hydroprocessing" or "hydrotreating" refers to processes or
treatments that react a hydrocarbon-based material with hydrogen,
typically under pressure and with a catalyst (hydroprocessing can
be non-catalytic). Such processes include, but are not limited to,
hydrodeoxygenation (of oxygenated species), hydrotreating,
hydrocracking, hydroisomerization, and hydrodewaxing. For examples
of such processes, see Cash et al., U.S. Pat. No. 6,630,066; and
Elomari, U.S. Pat. No. 6,841,063. Embodiments of the present
invention utilize such hydroprocessing to convert triglycerides to
paraffins. The terms "hydroprocessing" and "hydrotreating" are used
interchangeably herein.
"Isomerizing," as defined herein, refers to catalytic processes
that typically convert n-alkanes to branched isomers. ISODEWAXING
(Trademark of CHEVRON U.S.A. INC.) catalysts are representative
catalysts used in such processes. See, e.g., Zones et al., U.S.
Pat. No. 5,300,210; Miller, U.S. Pat. No. 5,158,665; and Miller,
U.S. Pat. No. 4,859,312.
"Transportation fuels," as defined herein, refer to
hydrocarbon-based fuels suitable for consumption by vehicles. Such
fuels include, but are not limited to, diesel, gasoline, jet fuel
and the like.
"Diesel fuel," as defined herein, is a material suitable for use in
diesel engines and conforming to the current version at least one
of the following specifications: ASTM D 975--"Standard
Specification for Diesel Fuel Oils"; European Grade CEN 90;
Japanese Fuel Standards JIS K 2204; The United States National
Conference on Weights and Measures (NCWM) 1997 guidelines for
premium diesel fuel; and The United States Engine Manufacturers
Association recommended guideline for premium diesel fuel
(FQP-1A).
The term "biodiesel," as used herein, refers to diesel fuel that is
at least significantly derived from a biological source, and which
is generally consistent with ASTM International Standard Test
Method D-6751. Often, biodiesel is blended with conventional
petroleum diesel. B20 is a blend of 20 percent biodiesel with 80
percent conventional diesel. B100 denotes pure biodiesel.
"Conventional biodiesel," as defined herein, refers to ester-based
biodiesel produced via a transesterification of
triglyceride-containing vegetable oils.
A "conventional refinery," as defined herein, refers to the
infrastructure utilized in the processing of petroleum to yield
fuels, lubricants, and/or other petrochemical products.
A "Generation 1 biofuel," as defined herein, is any biofuel whose
production adversely impacts the food chain.
A "Generation 2 biofuel," as defined herein, is any biofuel whose
production is independent of the food chain.
"Pour point," as defined herein, represents the lowest temperature
at which a fluid will pour or flow. See, e.g., ASTM International
Standard Test Methods D 5950-96, D 6892-03, and D 97.
"Cloud point," as defined herein, represents the temperature at
which a fluid begins to phase separate due to crystal formation.
See, e.g., ASTM Standard Test Methods D 5773-95, D 2500, D 5551,
and D 5771.
As defined herein, "C.sub.n," where "n" is an integer, describes a
hydrocarbon or hydrocarbon-containing molecule or fragment (e.g.,
an alkyl or alkenyl group) wherein "n" denotes the number of carbon
atoms in the fragment or molecule--irrespective of linearity or
branching.
"Dynamic adaptability," as defined herein, refers to an inherent
ability to accommodate changes in feedstock composition and/or
desired intermediate and/or product output.
3. Methods
As mentioned previously, and with reference to FIG. 1, in some
embodiments the present invention is directed to one or more
methods for integrating biomass processing so as to afford dynamic
adaptability in the production of biofuels and/or other bio-derived
products, such methods comprising the steps of: (Step 101) treating
a triglyceride-containing biomass (Biomass I) so as to yield a
triglyceride fraction comprising triglycerides and a
non-triglyceride fraction; (Step 102) transesterifying a first
portion of the triglycerides in the triglyceride fraction to yield
monoesters; (Step 103) steam-reforming a second portion of the
triglycerides in the triglyceride fraction to yield bio-derived
H.sub.2; (Step 104) hydroprocessing at least a portion of the
monoesters with H.sub.2 in a hydroprocessing reactor to yield one
or more hydrocarbon products of a first type, wherein a portion of
the H.sub.2 so utilized is provided by at least a portion of the
bio-derived H.sub.2; and (Step 105) pyrolyzing at least a portion
of the non-triglyceride fraction (optionally with a Biomass II) to
yield a pyrolysis oil, at least a portion of which is
hydroprocessed in the hydroprocessing reactor to yield one or more
hydrocarbon products of a second type.
In some such above-described method embodiments,
triglyceride-containing biomass (Biomass I, or biomass of a first
type) typically is, or comprises, a vegetable oil that originates
from a biomass source selected from the group consisting of crops,
vegetables, microalgae, and combinations thereof. Accordingly, the
term "vegetable oil" is actually quite broad and can generally be
extended to include any biologically-derived oil (vide supra).
Those of skill in the art will recognize that generally any
biological source of lipids can serve as a source of biomass of a
first type from which a biologically-derived oil (e.g., vegetable
oil) comprising triglycerides can be obtained. It will be further
appreciated that some such sources are more economical and more
amenable to regional cultivation, and also that those sources from
which food is not derived may be additionally attractive (so as not
to be seen as competing with food). Exemplary vegetable oils/oil
sources include, but are not limited to, canola, soy, rapeseed,
palm, peanut, jatropha, yellow grease, algae, and the like. Biomass
containing triglycerides is referred to herein as
"triglyceride-containing biomass."
In some such above-described method embodiments, Biomass II
(biomass of a second type) can be generally of the same type as
Biomass I, and/or it can be different. In the latter case, it can
be triglyceride-containing, cellulosic and/or lignocellulosic
(e.g., wood). For a review of biomass and its associated
processing, see Huber et al., "Synthesis of Transportation Fuels
from Biomass: Chemistry, Catalysts, and Engineering," Chem. Rev.,
vol. 106, pp. 4044-4098, 2006. Note that in some embodiments, the
Biomass II further comprises waste plastic and/or other forms of
municipal solid waste (MSW).
In some such above-described method embodiments, the biomass
(Biomass I or II) undergoes some sort of pretreatment. Processing
and/or preprocessing of biomass can include, for example,
cultivating, harvesting, mechanical grinding, pelletization,
extraction, fermentation, separation, hydrolysis, and any
combination of such techniques, wherein such techniques are
generally described in Huber. Those of skill in the art will
appreciate that variations on such above-described preprocessing
techniques can be applied as various needs arise.
In some embodiments, when cellulosic/lignocellulosic biomass is
used, methods can benefit from cryogenic processing, wherein
cryogenic temperatures (e.g., liquid N.sub.2) are used to
facilitate the crushing of such fiber-based biomass, leading to
improvements in the hydrolysis of such cellulose and hemicellulose.
This will be described more fully by way of example (vide
infra).
In some above-described method embodiments, the step of pyrolyzing
involves a co-pyrolysis of the non-triglyceride fraction with a
secondary biomass (i.e., Biomass II). Such pyrolysis techniques are
known in the art and can be used and/or adapted for a variety of
feeds. See, e.g., Lappas et al., "Biomass pyrolysis in a
circulating fluid bed reactor for the production of fuels and
chemicals," Fuel, vol. 81, pp. 2087-2095, 2002; and Chen et al.,
"Catalytic pyrolysis of biomass for hydrogen rich fuel gas
production," Energy Conversion & Management, vol. 44, pp.
2289-2296, 2003.
In some above-described method embodiments, a portion of the
monoesters are steam-reformed with the triglycerides to yield
bio-derived H.sub.2 (and CO). Steam-reforming of biomass is known
in the art, see, e.g., Wang et al., "Biomass to Hydrogen via Fast
Pyrolysis and Catalytic Steam Reforming of the Pyrolysis Oil or Its
Fractions," Ind. Eng. Chem. Res., vol. 36, pp. 1507-1518, 1997; and
Marquevich et al., "Steam Reforming of Sunflower Oil for Hydrogen
Production," Ind. Eng. Chem. Res., vol. 39, pp. 2140-2147,
2000.
In some such above-described method embodiments, the bio-derived
H.sub.2 is stripped of CO prior to it being introduced into the
hydroprocessing reactor. In some or other such above-described
method embodiments, at least some of the bio-derived H.sub.2, as
syngas, is used to make products via Fischer-Tropsch (FT)
synthesis. Naturally, for FT synthesis, some or all of the CO could
be retained. For a review of Ficher-Tropsch synthesis, see Dry,
"The Fischer-Tropsch process: 1950-2000," Catalysis Today, vol. 71,
pp. 227-241, 2002.
In some such above-described method embodiments, the step of
hydroprocessing involves a hydroprocessing/hydrotreating catalyst
and a hydrogen-containing environment. For a general review of
hydroprocessing/hydrotreating, see, e.g., Rana et al., "A Review of
Recent Advances on Process Technologies for Upgrading of Heavy Oils
and Residua," Fuel, vol. 86, pp. 1216-1231, 2007. For an example of
how triglycerides can be hydroprocessed to yield a paraffinic
product, see, e.g., Craig et al., U.S. Pat. No. 4,992,605.
In some such above-described method embodiments, the step of
hydroprocessing involves or otherwise utilizes a hydrotreating
catalyst comprising an active metal or metal-alloy hydrotreating
catalyst component that is operationally integrated with a
refractory support material. In some such embodiments, the active
metal catalyst component is selected from the group consisting of
cobalt-molybdenum (Co--Mo) catalyst, nickel-molybdenum (Ni--Mo)
catalyst, noble metal catalyst, and combinations thereof. In these
or other embodiments, the refractory support material typically
comprises a refractory oxide support such as, but not limited to,
Al.sub.2O.sub.3, SiO.sub.2--Al.sub.2O.sub.3, and combinations
thereof. In some particular embodiments, the hydroprocessing step
makes use of an alumina-supported nickel-molybdenum catalyst.
Variation on catalyst type can be used to vary the type of
hydrocarbon products produced.
In some such above-described method embodiments, the
hydroprocessing is carried out at a temperature between 550.degree.
F. and 800.degree. F. In some such embodiments, the hydroprocessing
is carried out under a H.sub.2 partial pressure of between 400
pounds-force per square inch gauge (psig) and 2000 psig. In some or
other such embodiments, the hydroprocessing is carried out under a
H.sub.2 partial pressure of between 500 psig and 1500 psig. As with
catalyst type, such conditions can play a deterministic role in
what types of hydrocarbon products are produced.
In some above-described method embodiments, intermediate divergent
pathways afford dynamic process adaptability. In some or other such
above-described method embodiments, intermediate product output
from the multiple intermediate product streams is amenable to
dynamic variation. In some presently-contemplated embodiments, at
least some of the intermediate product stream(s) are directed
(physically) to one or more process steps for producing one or more
additional and/or alternative product species.
In some such above-described method embodiments, the one or more
hydrocarbon products of the first and second type are independently
selected from the group consisting of Generation 1 biofuels,
Generation 2 biofuels, biolubricants, biologically-derived
petrochemicals, and combinations thereof.
In some such above-described method embodiments, one or more
hydrocarbon products of the first and/or second type are a
transportation fuel. Such transportation fuels include, but are not
limited to, gasoline, jet fuel, E85, diesel fuel, and the like.
Generally, such transportation fuels possess a pour point and cloud
point rendering them acceptable for use in specific vehicles,
wherein a government regulatory agency and/or a standards
organization establishes the acceptable thresholds and/or ranges
for such properties. In some or other such above-described method
embodiments, one or more hydrocarbon products of the first and/or
second type are blended with other fuels of a biological and/or
petrochemical origin.
In some such above-described method embodiments, the
biologically-derived petrochemicals are selected from the group
consisting of esters, organic acids, alcohols, alkenes, alkanes,
and combinations thereof. The specific type and molecular weight of
such species can be tailored to meet current or anticipated
demands. For example, production of straight chain C.sub.5 alkanes
might yield to the production of branched C.sub.16 alkanes.
In some such above-described method embodiments, the one or more
hydrocarbon products of the first and second type are provided via
multiple product streams. In some such embodiments, one or more of
such product streams can be further directed to subsequent
processing/treatment, wherein some such streams provide precursors
and/or intermediates for further processing/treatment.
In some such above-described embodiments, one or more of the
hydrocarbon product streams (or fractional streams thereof) are
subjected to an additional step of isomerizing, i.e.,
isomerization. Typically, such isomerization is carried out using
an isomerization catalyst. Such isomerization catalysts have
traditionally comprised Pt or Pd on a support such as SAPO-11,
SM-3, SSZ-32, ZSM-23, ZSM-22, and similar such supports; and/or on
an acidic support material such as beta or zeolite Y molecular
sieves, SiO.sub.2, Al.sub.2O.sub.3, SiO2-Al.sub.2O.sub.3, and
combinations thereof. Traditionally, the isomerization is carried
out at a temperature between about 500.degree. F. and about
750.degree. F. The operating pressure is typically 200 to 2000
psig, and more typically 200 psig to 1000 psig. Hydrogen flow rate
is typically 50 to 5000 standard cubic feet/barrel (SCF/barrel).
For other suitable isomerization catalysts, see, e.g., Zones et
al., U.S. Pat. No. 5,300,210; Miller, U.S. Pat. No. 5,158,665; and
Miller, U.S. Pat. No. 4,859,312.
4. Systems
As already mentioned in a previous section, and with reference to
FIG. 2, in some embodiments the present invention is directed to
one or more systems 200 for implementing the above-described
methods, such systems comprising: an extraction unit 201 for
treating a triglyceride-containing biomass so as to yield a
triglyceride fraction comprising triglycerides and a
non-triglyceride fraction; a transesterification unit 202 for
transesterifying a first portion of the triglycerides in the
triglyceride fraction to yield monoesters; a steam-reforming unit
203 for converting a second portion of the triglycerides in the
triglyceride fraction into bio-derived H.sub.2; a hydroprocessing
reactor 204 for hydroprocessing at least a portion of the
monoesters with H.sub.2 to yield one or more hydrocarbon products
of a first type, wherein a portion of the H.sub.2 so utilized is
provided by the bio-derived H.sub.2; and a pyrolysis unit 205
operable for pyrolyzing at least a portion of the non-triglyceride
fraction to pyrolysis oil, at least a portion of which is
hydroprocessed in the hydroprocessing reactor to yield one or more
hydrocarbon products of a second type.
In some such above-described system embodiments, pyrolysis unit 205
is further operable for co-pyrolyzing the non-triglyceride fraction
with a secondary biomass, wherein the secondary biomass is selected
from the group consisting of triglyceride-containing biomass,
lignocellulosic biomass, cellulosic biomass, and combinations
thereof.
In some such above-described system embodiments, the
steam-reforming unit 203 is operable for co-reforming a portion of
the monoesters with the triglycerides to yield bio-derived H.sub.2,
wherein said co-reforming is done either sequentially or in
parallel.
In some above-described system embodiments, the system is
configured such that intermediate divergent pathways afford dynamic
process adaptability. Such dynamic process adaptability affords an
ability to react "on-the-fly" to input variations and/or changes in
product amount or type. Such flexibility enhances the overall
economics of such processing.
In some above-described system embodiments, the system further
comprises a stripping unit for stripping CO from the bio-derived
H.sub.2. Alternatively, wherein some or all of the H.sub.2 is
utilized for Fischer-Tropsch synthesis (e.g., in a Fischer-Tropsch
unit), some or all of the CO can be retained such that H.sub.2+CO,
in appropriate ratios, can be utilized as syngas. Such additional
Fischer-Tropsch process(es) can provide for fuel and/or chemical
products.
In some such above-described system embodiments, the
hydroprocessing unit 204 utilizes a catalyst selected from the
group consisting of Co--Mo alloys, Ni--Mo alloys, noble metals, and
combinations thereof. Those of skill in the art will recognize that
other hydroprocessing catalysts could be similarly used, and that
any such catalysts may further employ a refractory support such as,
but not limited to, Al.sub.2O.sub.3, SiO.sub.2--Al.sub.2O.sub.3,
and the like.
In some such above-described system embodiments, the one or more
hydrocarbon products of the first and second type generated by said
system are independently selected from the group consisting of
Generation 1 biofuels, Generation 2 biofuels, biolubricants,
biologically-derived petrochemicals, and combinations thereof.
In some such above-described system embodiments, the one or more
hydrocarbon products of the first and second type generated by said
system are provided via multiple product streams. As in the case of
the intermediate divergent pathways (vide supra), in some such
embodiments, the system(s) is configured such that product output
from the multiple product streams is amenable to dynamic variation,
with similar results and advantages.
In some above-described system embodiments, such systems further
comprise one or more biomass preprocessing units, wherein such
units can serve to homogenize or otherwise facilitate the further
processing of the biomass. An exemplary such preprocessing unit
would be one that cryogenically treats lignocellulosic material for
enhanced hydrolysis (see Example 1).
In some above-described system embodiments, such systems further
comprise an isomerization unit that can subsequently treat any of
the product streams (as a whole or in part) so as to dewax or
otherwise isomerizes any such stream as deemed necessary.
Generally, all of the above-described system units are configured
for selectively-integrating the processing of bio-derived ester
species with the production of biofuels, in accordance with the
methods described in Section 3. Further, there is typically a
proximal relationship between the various units that comprise
system 200, but this need not always be the case. Such
relationships may be variously influenced by existing
infrastructure and other economic considerations.
5. Variations
In addition to the above-described embodiments, in some
variously-contemplated alternative embodiments the above-described
methods and systems are further integrated, wholly or in part, with
one or more methods and systems of a conventional refinery. For
example, the bio-derived H.sub.2 can be used to hydroprocess
conventional petroleum in a conventional refinery. In such a
scenario, and while making this the primary use of the H.sub.2,
such bio-derived H.sub.2 could easily be diverted to the
manufacture of biofuels and/or other bio-derived chemical
products.
6. Example
The following example is provided to demonstrate particular
embodiments of the present invention. It should be appreciated by
those of skill in the art that the methods/systems disclosed in the
example which follows merely represent exemplary embodiments of the
present invention. However, those of skill in the art should, in
light of the present disclosure, appreciate that many changes can
be made in the specific embodiments described and still obtain a
like or similar result without departing from the spirit and scope
of the present invention.
EXAMPLE
This Example serves to illustrate a cryogenic preprocessing
technique for use in some embodiments of the present invention.
For processing of cellulose to glucose (via hydrolysis), the
efficiency of such hydrolysis is enhanced by a de-bundling of the
associated fibers (thereby increasing surface area), and by a
separation of the holocellulose (cellulose+hemicellulose) from
lignin (when the biomass is a lignocellulosic material).
Accordingly, the inventors have developed a method by which
cellulosic/lignocellulosic fibers are cryogenically treated with
liquid N.sub.2 (LN2) during a mechanical grinding process. As a
result, hydrolysis conditions were milder (reduced residence time,
lower temperatures) and used less acid.
7. Conclusion
In summary, the present invention provides for methods and systems
for processing biomass to selectively yield a variety of
hydrocarbon molecules and hydrogen as products, wherein some or all
of these products can be further utilized for other biomass
processing sub-processes, particularly wherein they lead to the
generation of biofuels and/or other high-value products. The
selective process integration and resulting dynamic adaptability
offer significant advantages over the existing art.
All patents and publications referenced herein are hereby
incorporated by reference to the extent not inconsistent herewith.
It will be understood that certain of the above-described
structures, functions, and operations of the above-described
embodiments are not necessary to practice the present invention and
are included in the description simply for completeness of an
exemplary embodiment or embodiments. In addition, it will be
understood that specific structures, functions, and operations set
forth in the above-described referenced patents and publications
can be practiced in conjunction with the present invention, but
they are not essential to its practice. It is therefore to be
understood that the invention may be practiced otherwise than as
specifically described without actually departing from the spirit
and scope of the present invention as defined by the appended
claims.
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